Method of forming refractive index distribution in light transmission path, and optical filter and method of using the same
AssigneeSumitomo Electric Industries, Ltd.
InventorHiroyuki Nakaishi
Life of this patent
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Abstract
A method of forming a refractive index distribution in a light transmission path including a core and a cladding layer involves steps of applying a photosensitive material layer to the surface of the cladding layer, forming a mask pattern of the photosensitive material layer through photolithography, and irradiating the light transmission path with an electromagnetic wave having a wavelength not exceeding that of visible light and especially a wavelength of X-rays; through the mask pattern, thereby forming in the core a refractive index fluctuation distribution corresponding to the mask pattern.
Claims46
A method of forming a refractive index distribution in a light transmission path, comprising the steps of:
- preparing a light transmission path including a core and a cladding layer;
- applying a photosensitive material layer onto a surface of said cladding layer;
- patterning said photosensitive material layer by photolithography thereby forming a mask pattern;
- and
- irradiating said light transmission path with an X-ray through said mask pattern, thereby forming in said core a refractive index fluctuation distribution corresponding to said mask pattern.
A method of forming a refractive index distribution in a light transmission path, comprising the steps of:
- preparing a light transmission path including a core and a cladding layer;
- applying a photosensitive material layer onto a surface of said cladding layer;
- patterning said photosensitive material layer by photolithography thereby forming a first mask pattern;
- covering a portion of said surface of said cladding layer that is exposed in a region of said first mask pattern with a metal layer;
- removing said first mask pattern for forming a second mask pattern consisting of said metal layer;
- and
- irradiating said light transmission path with an electromagnetic wave having a wavelength not exceeding that of visible light through said second mask pattern,
- thereby forming in said core a refractive index fluctuation distribution corresponding to said second mask pattern.
A method of forming a refractive index distribution in a light transmission path including a core and a cladding layer, comprising the steps of:
- forming a metal layer on a support film;
- patterning said metal layer to form a patterned metal layer pattern by photolithography, thereby forming a mask film including said support film and said patterned metal layer pattern;
- arranging said mask film so that said metal layer pattern approximates a surface of said cladding layer of said light transmission path;
- and
- irradiating said light transmission path with an X-ray through said mask film thereby forming in said core a refractive index fluctuation distribution corresponding to said metal layer pattern.
An optical filter comprising:
- a light transmission path including a core and a cladding layer, wherein said cladding layer has a thickness of not more than 50 .mu.m;
- and
- a fringy shielding pattern arranged periodically on a surface of said light transmission path.
A method of using an optical filter including a light transmission path having a core and a cladding layer, and a fringy shielding pattern periodically arranged on a surface of said light transmission path, comprising the steps of:
- irradiating an irradiated region of said core with an X-ray having an X-ray intensity through said shielding pattern while simultaneously transmitting and filtering light in said light transmission path;
- and
- adjusting at least either said X-ray intensity or a length of said irradiated region thereby dynamically controlling a filter characteristic of said optical filter.
Dependencies are inferred from the claim text.